After the wildly successful launch of Firefox 4 not all that long ago, it's hard to believe the next iteration of Mozilla's popular and free open source browser is already here.

Sure enough, though, Firefox 5 was officially released on Tuesday complete with a raft of new features that promise to give the browser yet another boost.

I've been playing around with Firefox 5 for some time already, and though it's not as big an upgrade as Firefox 4 was, it's been rock solid--and fast.

I wrote just last week about a number of the key new features appearing in the release candidate. Now that the final version is here, however, there's no more reason to delay. Here are five good reasons you should download Firefox 5 as soon as you can.

1. It Respects Your Privacy

Mozilla's Do Not Track feature gives users more control over the way their browsing behavior is tracked and used on the Web by allowing them to tell the websites they visit that they want to opt out of online behavioral tracking. Now, in Firefox 5, Do Not Track is even easier to find in the Firefox Preferences section.

Also of note is that Firefox 5 for Android includes the Do Not Track feature as well, making Firefox the first browser to support Do Not Track on multiple platforms, Mozilla says.

2. It's Small and Fast

I've been feeling like Firefox 5 is faster, and that impression was recently confirmed over at Digitzor, which ran it through a bunch of benchmarks. Firefox actually blew away both Chrome and Opera on the SunSpider JavaScript test, in particular (no other browsers were included), and its cold start time compared very well with that of Google's Chrome. Firefox 5 was also notable for taking up minimal RAM, even with 25 websites opened.

3. It Supports an Open Web

With improved standards support for HTML5, XHR, MathML, SMIL and canvas, Firefox 5 is the best browser choice for an open Web. The new Firefox Add-on SDK for Windows, Mac and Linux enables local development of add-ons, meanwhile, and the Firefox Add-on Builder Beta provides a hosted Web-based build environment. The new version of the multiplatform software also adds support for CSS animations.

4. It Sports 1000 Improvements

It's actually more than 1000 improvements and performance enhancements that have been included in Firefox 5. They may not all be huge, noticeable user-interface changes, but they definitely make the software better.

The Android version of Firefox 5, meanwhile, includes a raft of bug fixes, improved page load speeds--especially on 3G networks--and added IPv6 support.

5. It's Secure, Independent and User-Driven

Firefox is open source software, which means it's not only developed with the help of users, but its security is continuously monitored and improved by a global community of users and developers. Mozilla, meanwhile, is an independent foundation. There's no way a proprietary browser maker like Microsoft -- or even a company like Google, which has its fingers everywhere -- can compete with that independence and user focus.

Firefox clearly faces stiff competition from Google's Chrome, but further improvements are on the way in Firefox 6 and beyond. You can download it here and see for yourself.

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